| 摘要 |
PURPOSE:To obtain an exhaust gas purifying catalyst having a wide NOx removing activity temp. range and excellent in the purifying function of exhaust gas with high oxygen content. CONSTITUTION:In a zeolite type catalyst having a metal seed supported thereon by ion exchange, an activity high temp. transfer type catalyst body 2 whose activity is transferred to a high temp. side at the time of heating in the presence of H2O and O2 is arranged on an upstream side 5 and an activity temp. region lasting catalyst body 3 of which the temp. region rich in activity is not changed under the same heating condition is arranged on a downstream side 6. By this constitution, the respective heat characteristics of both catalyst bodies 2, 3 arranged in combination are interpolated each other to provide a wide activity temp. region. An activity low temp. transfer type catalyst body can also be used in place of the activity high temp. transfer type catalyst body 2. |
